High speed digital zone control

Abstract

Disclosed is a high-speed approximation device that generates zone correction values in both the horizontal and vertical directions. Group correction values are stored for specific physical locations on the screen for each correction factor parameter. Higher resolution correction signals can be produced by generating zone correction values. Zone correction values are produced for binary fractional addresses that correspond to specific physical locations on the screen. By addressing specific binary fractional addresses that correspond to the location of the video image on the screen, new group correction values do not have to be produced each time the horizontal or vertical size or centering or frequency of the video image is changed. Additionally, by using start addresses and end addresses, zone correction values only have to be produced for the area which the video image occupies on the screen. The present invention also uses a high-speed binary fractional multiplier that multiplies a correction value by a series of binary numbers that simply shift the decimal location of the correction value to produce quotient values. Selection of the quotient values is made by a binary fractional address signal that indicates the specific address for the zone correction value to be generated. By transforming from an arbitrary line count address space to a binary physical address space, the present invention allows for the use of a simple and fast parallel binary fractional multiplier engine.

Description

A. Field of InventionThe present invention pertains generally to correcting the alignment of display devices and more particularly to digital zone control for correction and alignment of multimode display devices. This is achieved by determining the mapping of correction values for physical locations on a screen display using a high speed manner of generating incremental correction values between the physically located correction values and mapping the incremental correction values to scan lines using an approximation technique.B. Definitions"Address Quotient Value" means the physical division number divided by the number of scan lines of an image, for vertical geometry corrections, or by the number of pixels in a scan line, for horizontal geometry corrections."Physical Division Number" means the total number of physical divisions over that portion of the screen on which an image appears or that portion for which an image alignment is desired."Binary Order of Magnitude Number" means...

AI Technical Summary

Problems solved by technology

However, the generation of these correction waveforms using digital techniques requires the storage of a large amount of data in the form of correction values.

As the desire for enhanced resolution of these correction waveforms increases, the storage requirements cause these systems to be less economically attractive.

Additionally, certain correction factor parameters naturally require a very high resolution signal that necessitates a very large amount of correction value data.

To date, it has been uneconomical to provide digitally generated correction waveforms for these correction factor parameters.

However, difficulties have been encountered in providing satisfactory interpolation devices.

Typical interpolation engines use microprocessors or digital signal processors that are both expensive and normally too slow to process the interpolated correction values at the speed required to provide the interpolated data at the proper time.

Hence, the many different techniques that have been proposed h

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